With the development of the information society, various demands for display devices for displaying images are on the rise. In line with this, a variety of display devices have been recently developed and used, including LCDs (liquid crystal displays), PDPs (plasma display panels), ELDs (electroluminescent displays), VFDs (vacuum fluorescent displays), etc.
Among these display devices, those using organic light-emitting diodes (OLED) offer superior luminance and viewing angles compared to LCDs and can be made extremely thin because they work without a backlight unit.